KR100818687B1 - Dual segment molded lead frame connector for optical transceiver modules - Google Patents

Abstract

The present invention describes lead frame connectors for connecting optical sub-assemblies to a printed circuit board in an optical transceiver module. Lead frame connectors 102 include a stamped and bent conductive lead structure 110 in a plurality of insert injection molded plastic cases 112, 114. Plastic cases provide mechanical support to the finished component as well as electrical insulation to the conductors in the lead frame. Lead frame connectors are connected to leads connected to the optical sub-assemblies and mounted on a printed circuit board surface to establish a connection between the optical sub-structure and the printed circuit board.

Lead Frame Connectors, Conductors, Printed Circuit Boards

Description

Lead Frame Connector for Two-Part Molded Optical Transceiver Module {DUAL SEGMENT MOLDED LEAD FRAME CONNECTOR FOR OPTICAL TRANSCEIVER MODULES}

The present invention relates generally to an optical transceiver module. More specifically, the present invention relates to a lead frame molded into two parts used to connect an optical sub-assembly to a printed circuit board in an optical transceiver module.

Optical transceivers are used to transmit and receive optical signals from optical communication networks and to enable telecommunication networks to interact and communicate with optical networks. Many optical transceivers are modular and designed according to industry standards that define the mechanical aspects, form factors, optical and electrical needs of the transceiver, and other characteristics and needs of the transceiver. For example, the Small Form-Factor Module Multi-Source Agreement (SFF MSA), the Small Form-Factor Pluggable Module Multi-Source Agreement (SFP MSA), The 10 Gigabit Small Form-Factor Pluggable Module Multi-Source Agreement (XFP MSA) Revision 3.1 defines such standards. Each of these documents is incorporated herein by reference in its entirety.

The basic optical components of a traditional transceiver include a transmitter optical sub-assembly (TOSA) and a receiver optical sub-assembly (ROSA). The TOSA receives an electrical signal from a host device through the circuitry of the transceiver module and then generates a corresponding optical signal that is transmitted to a distant node in the optical communication network. In contrast, the ROSA receives the incoming light signal and then outputs a corresponding electrical signal that can be used or processed by the host device. In addition, most transceivers include a rigid printed circuit board (PCB) that includes control circuitry for TOSA and ROSA, among others.

The connection between the optical sub-assemblies in the transceiver module and the PCB has a variety of electrical and mechanical requirements. One of the most common electrical connection components used in traditional optical transceiver modules is a flexible printed circuit board, or "flex circuit," which connects the rigid printed circuit board of the module to the leads connected to the TOSA or ROSA. Flex circuits have several advantages, including good electrical performance and radio frequency response. Advantageously, the flex circuit also has the ability to improve tolerances within the module and withstand the pressures that occur during the manufacture and operation of the module.

While flex circuits have recently been widely used in optical transceiver modules, flex circuits represent a significant portion of the cost and labor required to manufacture transceiver modules. As the price of transceiver modules fell, the price associated with flex circuits continued to increase over the total price of transceiver modules. Due to the nature of the flex circuit, the cost of producing the flex circuit is generally higher than the price of a PCB that performs the same function.

Other approaches to connecting optical sub-assemblies to printed circuit boards have been recently introduced. For example, the leads protruding from the TOSA and ROSA may be bent into a shape such that the leads are directly coupled or connected to the printed circuit board. These techniques are often less expensive than using flex circuits, but they can result in undesirable radio frequency (RF) responses due to the inability to carefully control the impedance. In addition, bending the leads of the TOSA and ROSA will lead to poor reliability due to the possibility of damaging the glass seals or other brittle parts of the header assemblies within the TOSA and ROSA, each having a laser and a photodetector. Can be.

Because of the potential for damaging TOSA and ROSA and poor electrical performance, bending the leads of TOSA and ROSA, which allows the TOSA and ROSA to be directly connected to a printed circuit board, is not suitable for many transceiver modules. This approach is particularly unsuitable for relatively high speed transceiver modules where the RF response of the conductor is more important.

Embodiments of the invention relate to lead frame connectors used to electrically and mechanically connect an optical sub-assembly to a printed circuit board in an optical transceiver module. Lead frame connectors allow optical sub-assemblies to be connected to printed circuit boards in optical transceiver modules in a reliable and inexpensive manner. The use of lead frame connectors eliminates the need for flexible printed circuit boards used in traditional transceiver modules.

According to one embodiment, the lead frame connector includes a stamped and bent conductive lead structure that can be encased in a case. The case provides mechanical support to the finished component as well as electrical insulation to the conductors in the lead frame. In one embodiment, the case may be an insert injection molded plastic case. Lead frame connectors connect the leads with the optical sub-assemblies. The lead frame connector may also be mounted to a surface on the printed circuit board to establish a connection between the optical sub-assembly and the printed circuit board. The lead frame connector can be used with the transmitter optical subassembly and the receiver optical sub-assembly and can have any required number of leads.

Another embodiment of the invention includes a stamped and bent conductive lead structure that can be placed in two cases. The conductive lead structure and the two cases may be coplanar during the casting process. This makes it easier than ever to make the tools needed to produce lead frame connectors. In one embodiment, the cases may be insert injection molded plastic cases. The case provides mechanical support to the finished component as well as electrical insulation to the conductors in the lead frame. The conductive lead structure of the lead frame connector connects the lead with the optical sub-assembly. In this embodiment, the two cases allow the conductive leads to bend after the casting process. This makes it easy to install on the surface on the printed circuit board to establish the connection of the optical sub-assembly and the printed circuit board. The lead frame connector can be used with the transmitter optical subassembly and the receiver optical sub-assembly and can have any required number of leads.

One advantage of embodiments of the lead frame connectors of the present invention is that they can be designed to produce the desired electrical performance and RF response. This result can be achieved due to the possibility of controlling the impedance by controlling the width and shape of the conductor and the spacing between the conductors. In addition, the electrical properties of the materials used in the case can be taken into account when designing the electrical circuit of the module. Exemplary embodiments of the lead frame connector of the present invention are also easier to manufacture than currently used lead frame connectors. In addition, the components of the lead frame connector of the present invention are less expensive than the components of the corresponding flex circuit.

These and other objects and features of the present invention will become more apparent from the following detailed description and the appended claims, and will be learned by examples of the invention which will be described later.

To obtain other advantages and features of the present invention described above, a more specific detailed description of the invention briefly mentioned above will be made with reference to the specific embodiments described in the accompanying drawings. It is understood that these drawings represent only exemplary embodiments of the present invention and do not limit its scope, and the present invention will be described in more detail and specifically with reference to the following drawings.

1A shows a perspective view of a lead frame connector corresponding to a ROSA constructed in accordance with one exemplary embodiment of the present invention;

1B shows a perspective view of a TOSA and corresponding lead frame connector constructed in accordance with another embodiment of the present invention;

FIG. 2A shows a top view of the ROSA lead frame connector of FIG. 1A; FIG.

FIG. 2B shows a perspective view of the conductive lead of the lead frame of FIG. 1A; FIG.

2C-2F illustrate various views of the ROSA lead frame connector of FIG. 1A;

FIG. 3A shows a top view of the TOSA lead frame connector of FIG. 1B; FIG.

FIG. 3B shows a perspective view of the conductive leads of the lead frame of FIG. 1B;

3C-3F show various views of the ROSA lead frame connector of FIG. 1B;

4A shows a perspective view of a lead frame connector corresponding to a ROSA that can be constructed in accordance with another exemplary embodiment of the present invention;

4B shows a perspective view of the ROSA and lead frame connector of FIG. 4A in assembled form;

4C shows a perspective view of a conductive lead in the lead frame of FIGS. 4A and 4B in a shape that is not bent prior to casting;

4D shows a side view of the assembled lead frame connector of FIG. 4B;

5A shows a perspective view of a TOSA and a corresponding lead frame connector constructed in accordance with another exemplary embodiment of the present invention;

FIG. 5B shows a perspective view of the lead frame connector and ROSA of FIG. 5A in assembled form ready for casting mounting; FIG.

FIG. 5C shows a perspective view of a conductive lead in the lead frame of FIGS. 5A and 5B in a shape that is not bent prior to casting;

FIG. 5D shows a side view of the assembled lead frame connector of FIG. 5B;

6A and 6B are perspective views of opposite sides of a printed circuit board having the lead frame connectors of FIGS. 1 and 2 attached to the printed circuit board; And

7A and 7B are perspective views of opposite sides of a printed circuit board having the lead frame connector of FIGS. 3 and 4 attached to the printed circuit board.

The present invention relates to lead frame connectors used to electrically and mechanically connect optical sub-assemblies to a printed circuit board in an optical transceiver module. According to one embodiment, the lead frame connector may include a preformed lead frame disposed within the case or housing. The connector can be manufactured by casting a case around the lead frame. In another embodiment, the lead frame connector includes a two-part case around the lead frame or assembly. The lead frame or assembly can be mounted or placed in a case or housing while at the same time it lies within a single plane to make the necessary tools and to make the lead frame connector easier. The lead frame connector of the present invention connects the leads to the optical sub-assemblies. Lead frame connectors may also be mounted to a surface on a printed circuit board to establish a connection between the optical sub-assembly and the printed circuit board.

The lead frame connectors of the present invention provide several advantages over using flex circuits or other traditional techniques. Compared to flex circuits, lead frame connector components are significantly cheaper. In addition, the process of manufacturing transceiver modules using lead frame connectors may require less labor through increased automation. Compared to simply bending the lead of an optical sub-assembly allowing direct connection to the PCB, the lead frame connector has significantly better electrical performance and RF response. In addition, there is no significant risk of damaging the brittle portions of the optical sub-assembly during the process of connecting the optical sub-assembly to the PCB.

1, lead frame connector structure

1A illustrates a ROSA 10 and corresponding lead frame connector 12 that may be constructed in accordance with an embodiment of the invention. ROSAs typically have five leads 14 and the lead frame connector 12 of FIG. 1A has five corresponding electrical contacts 16. These contacts are in electrical connection with five corresponding conductors or leads 18. 1B shows a TOSA 20 and corresponding lead frame connector 22 that may be constructed in accordance with an embodiment of the present invention. TOSAs typically have four leads 24 and the lead frame connector 22 of FIG. 1B has four corresponding electrical contacts 26. Like the lead frame connector 12 of FIG. 1A, the contacts 26 are electrically connected with five corresponding conductors or leads 28. Although the lead frame connectors of FIGS. 1A and 1B have four and five electrical contacts and leads, respectively, the principles of the invention disclosed herein form lead frame connectors having any number of electrical contacts and / or leads. It can be applied to

2A and 2C-2F show various views of the ROSA lead frame connector 12 of FIG. 1A. 2B shows the lead frame 30 without a case 32 that may be disposed around the lead frame 30. The case 32 provides electrical insulation to the conductors or portions of the leads 18 of the lead frame 30 as well as mechanical support to the finished components. FIG. 2B shows the lead frame 30 as shown in FIGS. 1A and 1B before the five leads in the process to be described in more detail below are electrically separated from each other. 3A-3F show corresponding views of the TOSA lead frame connector 22 of FIG. 1B.

2A-2F and 3A-3F, electrically insulating case 32 has a surface 36 defining a plane. In the illustrated embodiment, the plurality of electrical contacts 16 are aligned in a shape generally parallel to the plane defined by the case 32. As also shown, the conductors or leads 18 may extend from the electrical contacts 16 and be bent in three dimensions, such that in the illustrated embodiment, at least a portion of the plurality of leads 18 may be in the case 32. Extend out of the case 32 in a direction not parallel to the plane defined by. Of course, depending on the position of the optical sub-assemblies and the printed circuit board in any particular optical transmit / receive module, the conductors or leads 18 can be bent in any desired direction.

The lead frame connectors 12 and 22 of FIGS. 1A and 1B give the desired electrical performance and RF response. These results can be achieved because of the ability to control impedance based on the width and shape of the conductors or leads 18 and the fact that the spacing between the conductors or leads 18 can be carefully controlled. The shape, position, and dimensions of conductors or leads 18 in lead frame connectors 12 and 22 may be selected based on electrical and RF conditions experienced in any particular application. Prior to beginning the manufacturing process for lead frame connectors 12 and 22, computer simulations of various designs may be performed to identify those designs that produce acceptable RF responses. The material used to cast the lead frame connectors 12 and 22 may be selected to have an appropriate dielectric constant determined by the simulation process, or optionally, the dielectric coefficient may be used as an input to the simulation process. have. For example, the material forming the cases 12 and 22 may be a polymer, including but not limited to thermoplastic and thermoset materials, synthetic materials, or other materials that can function as dielectric or insulation. . The electrical performance of lead frame connectors 12 and 22 is particularly important in relatively high frequency transceiver modules that operate as high as 1, 2, 4 or 10 gigabits per second (Gbit / s). Exemplary embodiments of the lead frame connectors of the present invention can be used with some of these modules while exhibiting acceptable RF responses.

4A and 4B illustrate a ROSA 100 and corresponding lead frame connector 102 that may be constructed in accordance with another exemplary embodiment of the present invention. 4A shows the ROSA 100 and lead frame connector 102 before assembly. 4B shows two parts assembled into one exemplary working shape. One advantage of this exemplary embodiment is that the lead frame connector 102 may be used in the assembly process after the process used to place the conductors or leads in the case, or as part of such a process, but not as part of such a process. It can be manipulated into a shape that works as part.

Like the ROSA 10 of FIG. 1A, the ROSA 100 has five leads 104 extending from one end 106. Lead frame connector 102 has five corresponding electrical contacts 108 at five ends 109 of each of the conductors or leads 110. The electrical contacts 108 may be aligned with the leads 104 of the ROSA 100. The lead frame connector 102 may include a first case 112 and a second case 114, which may each support a portion of the conductors 110. As shown, the first ends 109 of the five conductors 110 are contained within the first case 112. The second end 120 of the conductors 110 extends through the second case 114. In another embodiment, the electrical contacts 108 may be retained within a fixed portion rather than completely contained therein by the first case 112.

In one exemplary use of the lead frame 102, the ends 120 of the five conductors 110 extending from the second case 114 are, for example, sized and shaped contact points to be connected to the PCB. Function or function. One advantage of this form of lead frame connector 102 is that case 112 and case 114 may be coplanar during the manufacturing process. The two cases 112, 114 and conductors 110 may generally be aligned in a parallel plane, optionally in the same plane, during the manufacturing process, and the second case 114 may be aligned with the first case 112 during the assembly process. Headed for). The five conductors 110 are then manipulated or bent to the desired shape at a location between the first case 112 and the second case 114 and / or at a location adjacent to the second case 114 as part of the assembly process. Can lose. This will be explained in more detail below.

5A and 5B illustrate a TOSA 130 and corresponding lead frame connector 132 that may be constructed in accordance with another embodiment of the present invention. 5A shows the TOSA 130 and lead frame connector 132 before assembly. 5B shows two parts assembled in one exemplary form of operation. One advantage of this exemplary embodiment is that the lead frame connector 132 is in an operational shape as part of the assembly process after the process used to place the conductors or leads in the case, similar to the process mentioned for the ROSA 100. Can be formed.

Like the TOSA 20 of FIG. 1B, the TOSA 130 has four leads 134 extending from one end 136. The lead frame connector 132 has four corresponding electrical contacts 138 at the first end 139 of the conductors 140. The electrical contacts 138 may be aligned with the leads 134 of the TOSA 130. The lead frame connector 132 may include a first case 142 and a second case 144, each of which may support a portion of the conductors 140. As shown, the first ends 139 of the four conductors 140 are contained within the first case 142. In other embodiments, the electrical contacts 138 may be maintained in a fixed position without being completely contained therein by the first case 142. The second end 150 of the conductors 140 extends through the second case 144.

In one exemplary use of the lead frame 32, the ends 150 of the four conductors 140 are sized and shaped to, for example, be connected to a PCB. Like the lead frame connector 102, the two cases 142, 144 and the conductors 140 are generally aligned in parallel planes during the manufacturing process. In some embodiments, they may be coplanar. The four conductors 140 and the case 144 can then be manipulated until the second end 150 is in the desired position. As shown, the conductors 140 are bent at a position between the first case 142 and the second case 144 as part of the assembly process. This will be explained in detail below.

Lead frame connectors 102 and 132 of FIGS. 4A and 5A give the desired electrical performance and RF response. These results will be achieved by being able to control the impedance. The width and shape of the conductors 110 of the lead frame connector 102 and the conductors 140 of the lead frame connector 132 and the spacing between the conductors 110 and 140 can be carefully controlled. Impedances can be controlled by adjusting the shape, position and dimensions of conductors 110 and 140 in lead frame connectors 102 and 132 based on the electrical and RF conditions experienced in any particular application. Prior to commencing the manufacturing process for lead frame connectors 102 and 132, computer simulations of various designs may be performed to confirm those that produce acceptable RF responses.

In exemplary embodiments, the first and second cases 112, 114 of the lead frame connector 102, and the first and second cases 142, 144 of the lead frame connector 132 may be implanted. It may be manufactured using an injection molding process, a transfer molding process, or other casting processes known to those skilled in the art. Cases 112, 114, 142, and 144 may generally be made of a polymer, a synthetic material, or other materials that can function as a dielectric or insulator. Various types of non-limiting plastics, such as Liquid Crystal Polymer (LCP) and Polyetherimide (PEI), can be used here. One example of an LCP is Vectra® manufactured by Ticona Engineering Polymers. One example of PEI is Ultem® PEI from General Electric (GE) Plastics. In general, polymers with sufficient mechanical strength to withstand the bending process can be used. In some embodiments, it is desirable to use a material having an Underwriter's Laboratory (UL) 94V0 flammability. In other embodiments, it is desirable to use materials in exhaustive form that meet the Reduction of Hazardous Substance (ROHS) Directive 2002/95 / EC of the European Union, which is incorporated herein by reference. Among other things, the ROHS directive eliminates the use of halogen flame retardants and some heavy metals such as lead and cadmium to protect the environment. The LCP material described above shows both of these preferred features.

The plastic material used to cast the lead frame connectors 102 and 132 may be selected to have an appropriate dielectric coefficient as determined by the simulation process described above. Optionally, the dielectric coefficient can be used by entering the simulation process. The electrical performance of lead frame connectors 102 and 132 is particularly important for relatively high frequency transceiver modules operating at 1, 2, 4 or 10 Gbit / s or more. The lead frame connectors of the present invention can be used with some of these modules while exhibiting acceptable RF responses. Certain aspects of the design of lead frame connectors useful for achieving the desired electrical performance will be described below to meet other performance criteria.

Various factors can be considered to successfully design a lead frame connector that connects an optical assembly to a printed circuit board. These factors can sometimes be factors that mostly affect the physical design and most of them affect the electrical design. Physical design elements may include the layout of the lead frame connector, how the connector connects both the OSA and the printed circuit board, and how the end product withstands normal handling. Electrical design elements can include the selection of materials for the leads, the determination of the exact dimensions of the leads based on the desired frequency range in which the finished assembly will operate, the determination of the size and space of the circuits on the PCB, and the like.

One way of designing a balance of all the above mentioned elements is to use other software to design physical and electrical elements. For example, in one embodiment, Solidworks 3D Product Design software from SolidWorks Corporation is used to design the physical parts used for lead frame connectors, OSAs and PCBs. While simple electrical circuits are designed with known techniques, sophisticated 3D EM field solvers are needed to calculate the performance of more complex 3D shapes. In one embodiment, High Frequency Simulation Software, such as HFSS ^{™ from} Ansoft, can be used to design more complex electrical characteristics of lead frame connectors, OSAs, and PCBs. A single software could also be used to simulate changes in physical and electrical structures without having to use other software.

In one embodiment of the method, the physical features are designed using SolidWorks, and this design is passed to the HFSS program. Certain design factors that affect the electrical characteristics are then designed using HFSS. Changes indicated by specific test results can be implemented using appropriate software. For example, if you need to make a lead frame design so that physical changes are easier to connect, these changes can be made by SolidWorks and passed back to HFSS. Likewise, changes in specific components that affect electrical performance can be made directly within the HFSS, and new simulations are performed to determine the impact of the changes.

In the embodiment to be described herein. By way of non-limiting embodiment, the width, space and cross section thickness of the lead, the width, space and thickness of the pads on the PCB to which the lead frame is connected, and the space and / or location of the components and / or structures on the PCB The process can be used to determine. In some embodiments, lead frame 132 for TOSA 130 may be designed to use a 25 ohm single-ended impedance or another 50 ohm impedance. Optionally, lead frame 102 of ROSA 100 may be designed using a 50 ohm single-ended impedance or another 100 ohm impedance. The other impedances provide two signals with a 180 degree phase. As the signals propagate along a close path, phase shift helps to mitigate or even eliminate potential crosstalk and interference between the signals.

In another embodiment, and using the process described above, it is possible that the leads in both lead frame connectors 102, 132 may have a metal thickness of about 0.2 mm, a width of about 0.5 mm, and a separation gap of about 0.3 mm. Can be determined. Other dimensions are also possible and within the scope of the embodiments described herein, depending on the materials used in the leads and the case, and also depending on the particular frequency at which the lead frame / optical sub-assembly combination is designed. The above mentioned dimensions are provided strictly as an example of one possible set of dimensions of the lid.

While maintaining the ROHS standard described above, some special materials can be selected and tested to ensure acceptable electrical and RF performance for lead frame connectors and for the entire module. In one embodiment, the leads can be made from a copper-iron alloy (C194-Spring Hard) commonly used in semiconductor package lead frames. This material can, among other things, be selected for its excellent mechanical properties and performance. For example, the material may be flexible enough to allow for thermal expansion and contraction that occurs within the module without affecting the electrical properties of the lead frame. In addition, this flexibility allows the lead frames to be mechanically connected to the optical subassemblies and the PCB without containing unwanted pressure in the components. By making the pads on the PCB larger than the actual leads that are connected, the physical location of the leads on the PCB can be adjusted to allow mechanical alignment of the OSA, lead frame and PCB without sacrificing electrical performance. Those skilled in the art will appreciate that a wide variety of other materials and / or metal alloys may also be used in the lead frames of the present invention.

In one embodiment, the stamped lead frames can be plated with successive layers of nickel, palladium and gold prior to the plastic casting process. Such plating systems can be selected with excellent solderability. Because it is lead free (ROHS requirement) and does not exhibit the tin whisker problems associated with pure plating systems. Other plating materials can also be used.

2. Lead frame connector manufacturing process

One of the advantages of the exemplary embodiments of the lead frame connectors of the present invention is that they can be manufactured at much lower cost than traditional flex circuits used in optical transceiver modules. In addition to lead frame connectors, embodiments of the present invention also extend to methods of manufacturing lead frame connectors.

According to one embodiment, one exemplary method of manufacturing lead frame connectors 12 and 22 is performed using a reel-to-reel insert injection molding process. Reel-to-reel insert injection molding processes are generally known in the art, but have not previously been applied to the manufacture of connectors that can be used to connect optical sub-assemblies to printed circuit boards of optical transceiver modules.

This exemplary process of manufacture of lead frame connectors 12 and 22 may include stamping out a suitable conductor structure and shaping a ribon of conductive material. For example, the general conductor shape 18 shown in FIGS. 2B and 3B can be formed by stamping a piece of copper. The conductor shape can be easily chosen to match the conductor design determined to have acceptable electrical performance as described above.

The stamped piece is wound from one reel to another while passing through the insert injection molding process. During the exemplary process, the conductors of the engraved piece are bent and manipulated as needed in three dimensions to obtain the required three-dimensional conductor shape as shown in FIGS. 2B and 3B, for example. The insert injection molding process then forms a case around the lead frame, which provides mechanical support and electrical isolation for the conductor. While the reel to reel process is the cheapest process, it requires more complex tools and is typically used with very high volume occupancy. A smaller volume can be made in each elongate piece that includes one or more lead frames that are subsequently loaded onto the casting machine. Similarly, stamping is another high volume process, but lead frame conductors can also be etched using photochemical techniques within smaller volumes. The selection of a particular manufacturing process can be driven by an optimal tradeoff between tool price, part price, and volume without significant design changes to the parts.

After the case 32 is formed, the lead frame assembly may pass through a singulation die that dices pieces with casting cases into respective lead frame assemblies. During the preceding insert injection molding process, the respective conductors in the lead frame can be held together using part of the lead frame. In general, the lead frame manufacturing process uses a portion of the lead frame structure that mechanically stabilizes individual conductors during the stamping and casting process. Traditional lead frame fabrication processes typically use external stabilization, meaning that each conductor is connected to an external support structure that is typically stabilized and cut during the singulation step. The problem associated with the stabilization and singulation of this method is that conductive stubs often maintain electrical contact with the leads after this step. Quite large chips can act like antennas and degrade the RF response of lead frame structures.

According to one exemplary embodiment of the present invention, relatively large pieces are avoided by using the internal stabilizer shown in FIGS. 2B, 2D, 3B, and 3D by reference numeral 40. Stabilizer 40 may generally be similar to TOSA and ROSA connectors 12 and 22, the details of which are described herein with reference to ROSA connector 12 of FIGS. 2B and 2D. In particular, the five respective conductors of FIG. 2B are connected to each other with a "starburst" conductive stabilizer or structure 40 in a manner that provides mechanical stabilization during the casting process. This stabilizer 40 is in contrast to the external stabilization devices typically used in lead frame casting processes. After the casting process is finished, the conductive stabilizer 40 may be removed by punching or the like through the center or isolated hole 42 shown in FIG. 2D. This punching operation removes most of the conductive materials that stabilize the conductors and electrically separates the conductors from each other. This operation also leaves only trivial chunks that do not significantly degrade the RF response at high frequencies of 1, 2, 4 or 10 Gbit / second or higher.

Another exemplary embodiment of a method of manufacturing lead frame connectors 102 and 132 will be described with respect to FIGS. 4C 4D, 5C, and 5D. As with the previous method, the steps for making the lead frame connector 102 for the ROSA 100 are necessarily the same as the steps for making the lead frame connector 132 for the TOSA 130. The following description will describe the form of the lead frame connector 102. However, similar steps will occur for the lead frame connector 132.

Forming lead frame connector 102 may include stamping out a suitable conductor structure and forming a piece of conductive material. For example, a typical conductor shape for conductor 110 shown in FIG. 4C can be formed by stamping a piece of copper. The conductor shape can be easily chosen to match the conductor design determined to have acceptable electrical performance as described above. The conductors are then separated into respective conductors 110.

In this exemplary method, each conductor 110 may be held by an external stabilization device (not shown) at the second end 120. In some example embodiments, additional alignment pins may be used to stabilize the conductors 11 prior to the injection casting process. Because the casting process produces two separate cases 112, 114, in one exemplary embodiment additional alignment pins may be located between the cases at point 118 of FIG. 4A. Point 118 then becomes the point to bend in successive steps.

Once the conductors 110 are stabilized, both cases 112 and 114 may be injection casting using plastic having an appropriate dielectric constant. Ends 120 of conductors 110 may then be bent at a desired angle to create contact points where pads 152 (FIG. 7A) on PCB 150 may engage. As shown in FIG. 4, in one exemplary embodiment, the second ends 120 are bent twice in 90 degrees in the opposite direction to form contact points at the second end 120. Depending on the particular application, other angles are also possible. In another embodiment, the second ends 120 of the conductors 110 may be bent prior to the casting process.

An exemplary embodiment of this method of the present invention described above with reference to FIGS. 3 and 4 has many advantages over the previous system described above with reference to FIGS. 1 and 2. However, this exemplary embodiment also has additional advantages. Since the first and second cases can be coplanar during manufacture, it is much easier to manufacture the tools needed to produce the injection-injected part. In addition, the punch out step can be eliminated, saving additional manufacturing costs. Finally, the lead frame connectors 102, 132 can be held at their ends, making it easier to hold the connectors during the manufacturing process. No external hooks, protrusions, or chips are needed, and such hooks, protrusions, or chips need not be removed as part of the assembly process. In addition, the flattened shape provides unobstructed access to the solder joints when attaching the lead frame to the OSA.

3. Transceiver Manufacturing Process Using Lead Frame Connectors

6A and 6B show opposite sides of a printed circuit board 50 to which lead frame connectors 12 and 22 are attached. Exemplary embodiments of the invention described herein also extend a method of manufacturing or assembling optical transceiver modules using lead frame connectors 12 and 22. According to one embodiment, a method of manufacturing a transceiver module comprises connecting lead frames 12 and 22 to corresponding optical sub-assemblies 10 and 20. Since the process can be largely the same as for ROSA and TOSA, only the process of ROSA 10 will be described below.

ROSA lead frame connector 12 may be aligned with leads 14 protruding from the rear end of the ROSA. Leads 14 may pass through corresponding holes 44 in ROSA lead frame connector 12 and leads 14 may be soldered to the conductors of lead frame assembly 12. Passing the leads 14 through the holes 44 in the corresponding electrical contacts 16 is a practical self-alignment of the lead frame connector 12 with the optical sub-assembly 10. May be the result of As shown in FIG. 1A, the leads 14 of the ROSA 10 can be easily accessed from the opposite side 46 of the lead frame connector 12 to facilitate the soldering process. When soldering is performed, the combined ROSA 10 and lead frame connector 12 are then a surface mount device that can be mounted to the PCB 50.

Mounting the combined ROSA 10 and the lead frame connector 12 on the surface of the PCB 50 may be performed in various ways. As shown in FIG. 6B, the lead frame connector 12 may have a row of leads 18 that bend in a manner such that it contacts the corresponding row of pads 52 on the PCB 50. Since the leads 18 of the lead frame connector 12 are positioned to contact the pads 52, the physical connection is by manual soldering to the reverse flow of solder paste formed on the PCB 50. By means of a hot bar process or by other suitable techniques. Another option could be a fixture that facilitates the process of locating and soldering the lead frame connector 12 in contact with the PCB 5.

According to some embodiments of the invention, the process of connecting the combined ROSA 10 and lead frame connector 12 to the PCB 50 does not require an epoxy reinforcement and uses a flex circuit, for example. To avoid alignment handling problems experienced in traditional methods of connecting optical sub-assemblies to PCBs.

7A and 7B show opposite sides of a printed circuit board 150 having attached lead frame connectors 102 and 132. According to another exemplary embodiment of the present invention, a method of manufacturing a transceiver module may include connecting lead frames 102 and 132 to corresponding optical subassemblies 100 and 130. Since this process may be largely the same as for ROSA and TOSA of these embodiments described with reference to FIGS. 6A and 6B, attaching lead frame connectors 102, 132 to ROSA 100 and TOSA 130. The discussion of the specific steps involved in doing so will not be repeated here.

Mounting the combined ROSA 100 and the lead frame connector 102 on the surface of the PCB 150 may be performed in various ways. In one exemplary embodiment, the second case 114 may be bent at point 118 at a desired angle such that the contact points of the second end 120 are easily connected to the PCB 150. In the exemplary embodiment shown in FIGS. 7A and 7B, the second case 114 is bent at an angle of about 90 degrees. As shown in FIG. 7B, the lead frame connector 102 has a plurality of conductors 110 that bend in a manner such that the contact points contact each corresponding row of pads 152 on the PCB 150. Since the contact points of the lead frame connector 102 are positioned to contact the pads 152, the physical connection can be made by manual soldering, by the backflow of the solder fastening formed on the PCB 150, by a hot bar process, or by appropriate Can be made by other techniques. Another idea is to use fixtures that facilitate the process of placing a lead frame connector in contact with the PCB and soldering it.

In other embodiments, lead frame connectors 102 and 132 may be connected to OSA while in a straight, flat shape. Lead frame connectors 102 and 132 may then be bent at an appropriate angle, and the contact points of the leads may then be connected to pads 152 on PCB 150. In some embodiments, pads 152 may be slightly enlarged on PCB 150 to allow some movement of the alignment of the lead frame into the PCB. Mechanical alignment allows the OSA / lead frame / PCB package to be secured in a housing (not shown) so that the ferrule comprising optical fibers to connect the transceiver module can be correctly aligned.

According to certain embodiments of the present invention, the process of connecting the combined ROSA 10 and lead frame connector 102 to the PCB 150 does not require epoxy reinforcement and for example uses PCBs with flex circuits. It should be noted that it avoids the alignment handling problems experienced in traditional methods of connecting optical sub-assemblies to.

The invention can be embodied in other specific forms without departing from its spirit or essential characteristics. The above-described embodiments should be considered in terms of only illustrative and not restrictive.

Included in this specification.

Claims (21)

An electrically insulating case having a first case separate from the second case; And A plurality of conductors electrically isolated from each other by the electrically insulating case, Each of the plurality of conductors forms an electrical contact held within a fixed point with respect to the first case and a contact point extending from the second case, and bent at a position between the electrical contact and the contact point. Lead frame connector for connecting an optoelectronic device to a printed circuit board. The method of claim 1, And each of the contact points can be connected to a respective conductive structure on the printed circuit board. delete The method of claim 1, A first case and a second case of the electrically insulating case are insert injection molded over a portion of the plurality of conductors. The method of claim 1, And the first case encloses the plurality of conductors. Electrical contacts disposed within and electrically isolated in an electrically insulated case having a first case separate from the second case for attachment to the optical sub-assembly of the optical transceiver module, each held in a fixed position relative to the first case. And positioning a lead frame connector comprising a plurality of conductors forming contact points extending from the second case; Connecting the electrical contacts to corresponding leads of the optical sub-assembly to obtain a coupling structure comprising the lead frame connector and the optical sub-assembly; And Connecting the contact points to a corresponding conductive structure on a printed circuit board of the optical transceiver module to electrically connect the optical sub-assembly to a printed circuit board. The method of claim 6, Connecting the electrical contacts to corresponding leads of the optical sub-assembly, Passing each of the leads of the optical sub-assembly through a hole in a corresponding electrical contact; And Soldering the leads to the corresponding electrical contacts. The method of claim 7, wherein Soldering the leads to the corresponding electrical contacts is performed by soldering the electrical contacts on the side of the lead frame connectors against a side near the optical sub-assembly. How to. The method of claim 6, Connecting the contact points to the corresponding conductive structures on a printed circuit board Positioning contact points of the lead frame connector to contact the corresponding conductive structures; And Soldering the contact points to the conductive structures. The method of claim 7, wherein Soldering the leads to the corresponding electrical contacts includes using one of a hand soldering process, a hot bar process and a solder paste backflow. A method of manufacturing an optical transceiver module. The method of claim 6, Connecting the electrical contacts to corresponding leads of the optical sub-assembly may cause self-alignment of the lead frame connector with respect to the optical sub-assembly as the corresponding leads pass through holes in the electrical contacts. Method of manufacturing an optical transceiver module comprising a. The method of claim 6, Connecting the contact points comprises bending the conductors at a point between the first case and the second case. The method of claim 12, Connecting the contact points comprises bending the conductors at a location proximate the contact points to align the contact points with the conductive structures. delete Imprinting conductors of the selected type on the conductive ribbon; Placing each of the conductors in a fixed position relative to each other; And A case having a first case separate from the second case such that each of the conductors forms an electrical contact held in a fixed position relative to the first case and a contact point extending from the second case Casting to a lead frame connector. The method of claim 15, Bending the conductors at a point between the first case and the second case. The method of claim 15, Bending at least one of the conductors near the contact point. The method of claim 17, Said bending step includes forming a plurality of bends in at least one of said conductors near said contact point. The method of claim 15, Placing each of the conductors in a fixed position relative to each other further comprises securing the conductors near the contact point. The method of claim 15, And the first case and the second case are coplanar. The method of claim 15, Plating the extruded lead frames with successive layers of nickel, palladium and gold prior to the casting step.

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